1. Field of the Invention
The present invention relates to a magnetic recording member, and more particularly, to a magnetic recording member having excellent surface properties, excellent low-noise properties, and good travelling properties.
2. Description of the Prior Art
Nowadays, various kinds of high density magnetic recording devices are widely used, and among them, a video-recording device is used to record very short wave lengths. In video-recording, therefore, the contact between a magnetic head and a magnetic tape must be good so that the clearance loss between the head and the tape is reduced as much as possible, and thus even a slight unevenness on the surface of the video tape gives rise to various problems.
In order to improve the surface properties of a video tape, heretofore, the addition of binders having good surface properties, surface active agents, or the like, surface-treatments, and so on have been proposed. These methods are described in, for example, Japanese Patent Publication Nos. 14391/1965, 13181/1966, 28045/1972, 28046/1972, 28047/1973, and 5482/1973, and Japanese Patent Application (OPI) Nos. 37904/1972, 45522/1972 and 3506/1973.
Even with these methods, however, the surface properties are deteriorated and the noise level increases as the thickness of the magnetic layer decreases, and thus it has been found that serious practical difficulties are encountered with tapes produced by these methods when they are used as magnetic tapes for short wave length high density recording. This is because when the thickness of the magnetic layer is below a certain limit, the surface properties of the flexible support greatly influence the surface properties of the magnetic layer, that is, the surface properties of the magnetic layer are deteriorated if the surface properties of the flexible support are poor.
In accordance with prior art techniques, therefore, it has been impossible to eliminate the increase in the noise level encountered with a thin magnetic layer, and a good quality tape having a good signal-to-noise ratio (S/N ratio) has not been obtained.
On the other hand, a magnetic tape for high density recording must have good travelling properties. This is because a variation in the travelling causes a change in the sensitivity, a modulation of the signals producing noise, and so on. In order to improve the travelling properties, a layer has often been coated on the back of the tape. Examples of such coated layers are described in Japanese Patent Nos. 2613/1974, 32003/1972, and 10241/1974, and Japanese Patent Application (OPI) No. 17203/1974, etc.
In accordance with these methods, however, the surface properties of the magnetic layer are deteriorated due to the adhesion between the layer coated on the back of the tape and the magnetic layer, and a transfer of the layer coated on the back of the tape. As a result, magnetic tapes with high out-put, low noise, and good travelling properties have not been obtained.
Moreover, a method of matting the surface of the flexible support opposite the surface having the magnetic layer thereon is described in Japanese Patent Publication No. 6859/1966, and Japanese Patent Application (OPI) Nos. 28070/1972 and 97508/1973, etc. However, no suggestion exists in the prior art relative to the surface properties of the surface on which the magnetic layer is to be provided and the effects thereof, and a magnetic recording member with low noise and good travelling properties is not disclosed.